This is the devicetree schema for Microchip EMC1812/13/14/15/33
Multichannel Low-Voltage Remote Diode Sensor Family.
Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
---
.../bindings/hwmon/microchip,emc1812.yaml | 176 +++++++++++++++++++++
MAINTAINERS | 6 +
2 files changed, 182 insertions(+)
diff --git a/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..cc4c7bb53cb13416c1e9419cc8c6c8a56da22df8
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
@@ -0,0 +1,176 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/microchip,emc1812.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip EMC1812/13/14/15/33 multichannel temperature sensor
+
+maintainers:
+ - Marius Cristea <marius.cristea@microchip.com>
+
+description: |
+ The Microchip EMC1812/13/14/15/33 is a high-accuracy 2-wire multichannel
+ low-voltage remote diode temperature monitor.
+
+ The datasheet can be found here:
+ https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/EMC1812-3-4-5-33-Data-Sheet-DS20005751.pdf
+
+properties:
+ compatible:
+ enum:
+ - microchip,emc1812
+ - microchip,emc1813
+ - microchip,emc1814
+ - microchip,emc1815
+ - microchip,emc1833
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 2
+
+ interrupt-names:
+ description:
+ -alert-therm2 asserts when a diode temperature exceeds the ALERT
+ threshold.
+ -therm-addr asserts low when the hardware-set THERM limit threshold is
+ exceeded by one of the temperature sensors.
+ items:
+ - const: alert-therm2
+ - const: therm-addr
+
+ "#address-cells":
+ const: 1
+
+ "#size-cells":
+ const: 0
+
+ microchip,parasitic-res-on-channel1-2:
+ description:
+ Indicates that the chip and the diodes/transistors are sufficiently
+ far apart that a parasitic resistance is added to the wires, which can
+ affect the measurements. Due to the anti-parallel diode connections,
+ channels 1 and 2 are affected together.
+ type: boolean
+
+ microchip,parasitic-res-on-channel3-4:
+ description:
+ Indicates that the chip and the diodes/transistors are sufficiently far
+ apart that a parasitic resistance is added to the wires, which can affect
+ the measurements. Due to the anti-parallel diode connections, channels
+ 3 and 4 are affected together.
+ type: boolean
+
+ vdd-supply: true
+
+patternProperties:
+ "^channel@[1-4]$":
+ description:
+ Represents the external temperature channels to which
+ a remote diode is connected.
+ type: object
+
+ properties:
+ reg:
+ items:
+ minimum: 1
+ maximum: 4
+
+ label:
+ description: Unique name to identify which channel this is.
+
+ required:
+ - reg
+
+ additionalProperties: false
+
+required:
+ - compatible
+ - reg
+ - vdd-supply
+
+allOf:
+ - if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - microchip,emc1812
+ - microchip,emc1813
+ - microchip,emc1833
+ then:
+ properties:
+ microchip,parasitic-res-on-channel3-4: false
+ - if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - microchip,emc1812
+ then:
+ properties:
+ channel@1:
+ properties:
+ reg:
+ items:
+ const: 1
+ patternProperties:
+ "^channel@[2-4]$": false
+ - if:
+ properties:
+ compatible:
+ pattern: "^microchip,emc18[13]3"
+ then:
+ patternProperties:
+ "^channel@[12]$":
+ properties:
+ reg:
+ items:
+ maximum: 2
+ "^channel@[34]$": false
+ - if:
+ properties:
+ compatible:
+ pattern: "^microchip,emc1814"
+ then:
+ patternProperties:
+ "^channel@[1-3]$":
+ properties:
+ reg:
+ items:
+ maximum: 3
+ properties:
+ channel@4: false
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ temperature-sensor@4c {
+ compatible = "microchip,emc1813";
+ reg = <0x4c>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ microchip,parasitic-res-on-channel1-2;
+
+ vdd-supply = <&vdd>;
+
+ channel@1 {
+ reg = <1>;
+ label = "External CH1 Temperature";
+ };
+
+ channel@2 {
+ reg = <2>;
+ label = "External CH2 Temperature";
+ };
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 6d7b697bfdba16e4f0ee5f4f0195b9d7da06dae5..85c236df781e47c78deeb7ef4d80bc94bba604c4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16646,6 +16646,12 @@ S: Supported
F: Documentation/devicetree/bindings/interrupt-controller/microchip,sama7g5-eic.yaml
F: drivers/irqchip/irq-mchp-eic.c
+MICROCHIP EMC1812 DRIVER
+M: Marius Cristea <marius.cristea@microchip.com>
+L: linux-hwmon@vger.kernel.org
+S: Supported
+F: Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
+
MICROCHIP I2C DRIVER
M: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
L: linux-i2c@vger.kernel.org
--
2.48.1On Wed, Oct 29, 2025 at 05:50:58PM +0200, Marius Cristea wrote:
> This is the devicetree schema for Microchip EMC1812/13/14/15/33
> Multichannel Low-Voltage Remote Diode Sensor Family.
>
> Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
> ---
> .../bindings/hwmon/microchip,emc1812.yaml | 176 +++++++++++++++++++++
> MAINTAINERS | 6 +
> 2 files changed, 182 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..cc4c7bb53cb13416c1e9419cc8c6c8a56da22df8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
> @@ -0,0 +1,176 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/microchip,emc1812.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip EMC1812/13/14/15/33 multichannel temperature sensor
> +
> +maintainers:
> + - Marius Cristea <marius.cristea@microchip.com>
> +
> +description: |
> + The Microchip EMC1812/13/14/15/33 is a high-accuracy 2-wire multichannel
> + low-voltage remote diode temperature monitor.
> +
> + The datasheet can be found here:
> + https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/EMC1812-3-4-5-33-Data-Sheet-DS20005751.pdf
> +
> +properties:
> + compatible:
> + enum:
> + - microchip,emc1812
> + - microchip,emc1813
> + - microchip,emc1814
> + - microchip,emc1815
> + - microchip,emc1833
Could you add a note to the commit message about what makes these
devices incompatible with one another?
> +
> + reg:
> + maxItems: 1
> +
> + interrupts:
> + maxItems: 2
> +
> + interrupt-names:
> + description:
> + -alert-therm2 asserts when a diode temperature exceeds the ALERT
> + threshold.
> + -therm-addr asserts low when the hardware-set THERM limit threshold is
> + exceeded by one of the temperature sensors.
You should be able to just move this into interrupts:
interrupts:
items:
- description:
alert-therm2 asserts when a diode temperature exceeds the ALERT
threshold.
- description:
therm-addr asserts low when the hardware-set THERM limit threshold is
exceeded by one of the temperature sensors.
> + items:
> + - const: alert-therm2
> + - const: therm-addr
Also, should this and interrupts have minItems: 1? Are both actually
required? Can you have therm-addr without alert-therm2?
pw-bot: changes-requested
Cheers,
Conor.
> +
> + "#address-cells":
> + const: 1
> +
> + "#size-cells":
> + const: 0
> +
> + microchip,parasitic-res-on-channel1-2:
> + description:
> + Indicates that the chip and the diodes/transistors are sufficiently
> + far apart that a parasitic resistance is added to the wires, which can
> + affect the measurements. Due to the anti-parallel diode connections,
> + channels 1 and 2 are affected together.
> + type: boolean
> +
> + microchip,parasitic-res-on-channel3-4:
> + description:
> + Indicates that the chip and the diodes/transistors are sufficiently far
> + apart that a parasitic resistance is added to the wires, which can affect
> + the measurements. Due to the anti-parallel diode connections, channels
> + 3 and 4 are affected together.
> + type: boolean
> +
> + vdd-supply: true
> +
> +patternProperties:
> + "^channel@[1-4]$":
> + description:
> + Represents the external temperature channels to which
> + a remote diode is connected.
> + type: object
> +
> + properties:
> + reg:
> + items:
> + minimum: 1
> + maximum: 4
> +
> + label:
> + description: Unique name to identify which channel this is.
> +
> + required:
> + - reg
> +
> + additionalProperties: false
> +
> +required:
> + - compatible
> + - reg
> + - vdd-supply
> +
> +allOf:
> + - if:
> + properties:
> + compatible:
> + contains:
> + enum:
> + - microchip,emc1812
> + - microchip,emc1813
> + - microchip,emc1833
> + then:
> + properties:
> + microchip,parasitic-res-on-channel3-4: false
> + - if:
> + properties:
> + compatible:
> + contains:
> + enum:
> + - microchip,emc1812
> + then:
> + properties:
> + channel@1:
> + properties:
> + reg:
> + items:
> + const: 1
> + patternProperties:
> + "^channel@[2-4]$": false
> + - if:
> + properties:
> + compatible:
> + pattern: "^microchip,emc18[13]3"
> + then:
> + patternProperties:
> + "^channel@[12]$":
> + properties:
> + reg:
> + items:
> + maximum: 2
> + "^channel@[34]$": false
> + - if:
> + properties:
> + compatible:
> + pattern: "^microchip,emc1814"
> + then:
> + patternProperties:
> + "^channel@[1-3]$":
> + properties:
> + reg:
> + items:
> + maximum: 3
> + properties:
> + channel@4: false
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + i2c {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + temperature-sensor@4c {
> + compatible = "microchip,emc1813";
> + reg = <0x4c>;
> +
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + microchip,parasitic-res-on-channel1-2;
> +
> + vdd-supply = <&vdd>;
> +
> + channel@1 {
> + reg = <1>;
> + label = "External CH1 Temperature";
> + };
> +
> + channel@2 {
> + reg = <2>;
> + label = "External CH2 Temperature";
> + };
> + };
> + };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6d7b697bfdba16e4f0ee5f4f0195b9d7da06dae5..85c236df781e47c78deeb7ef4d80bc94bba604c4 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16646,6 +16646,12 @@ S: Supported
> F: Documentation/devicetree/bindings/interrupt-controller/microchip,sama7g5-eic.yaml
> F: drivers/irqchip/irq-mchp-eic.c
>
> +MICROCHIP EMC1812 DRIVER
> +M: Marius Cristea <marius.cristea@microchip.com>
> +L: linux-hwmon@vger.kernel.org
> +S: Supported
> +F: Documentation/devicetree/bindings/hwmon/microchip,emc1812.yaml
> +
> MICROCHIP I2C DRIVER
> M: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
> L: linux-i2c@vger.kernel.org
>
> --
> 2.48.1
>
Hi Conor, On Wed, 2025-10-29 at 18:25 +0000, Conor Dooley wrote: > On Wed, Oct 29, 2025 at 05:50:58PM +0200, Marius Cristea wrote: > > This is the devicetree schema for Microchip EMC1812/13/14/15/33 > > Multichannel Low-Voltage Remote Diode Sensor Family. > > > > Signed-off-by: Marius Cristea <marius.cristea@microchip.com> > > --- > > .../bindings/hwmon/microchip,emc1812.yaml | 176 > > +++++++++++++++++++++ > > MAINTAINERS | 6 + > > 2 files changed, 182 insertions(+) > > > ... > You should be able to just move this into interrupts: > interrupts: > items: > - description: > alert-therm2 asserts when a diode temperature exceeds the > ALERT > threshold. > - description: > therm-addr asserts low when the hardware-set THERM limit > threshold is > exceeded by one of the temperature sensors. > > > + items: > > + - const: alert-therm2 > > + - const: therm-addr > > Also, should this and interrupts have minItems: 1? Are both actually > required? Can you have therm-addr without alert-therm2? > Right now the driver doesn't support any interrupts, but it may support in future. The "alert-therm2" is a maskable interrupt and the "therm- addr" can't be masked and is "always enabled" into the chip. I didn't use "minItems: 1" because I wanted to leave to the user the decision if he needs any interrupts into their system > pw-bot: changes-requested > > Cheers, > Conor. > > > + > > + "#address-cells": > > + const: 1 > > + > > + "#size-cells": > > + const: 0 > > + Thanks, Marius
On Mon, Nov 03, 2025 at 04:35:27PM +0000, Marius.Cristea@microchip.com wrote: > Hi Conor, > > On Wed, 2025-10-29 at 18:25 +0000, Conor Dooley wrote: > > On Wed, Oct 29, 2025 at 05:50:58PM +0200, Marius Cristea wrote: > > > This is the devicetree schema for Microchip EMC1812/13/14/15/33 > > > Multichannel Low-Voltage Remote Diode Sensor Family. > > > > > > Signed-off-by: Marius Cristea <marius.cristea@microchip.com> > > > --- > > > .../bindings/hwmon/microchip,emc1812.yaml | 176 > > > +++++++++++++++++++++ > > > MAINTAINERS | 6 + > > > 2 files changed, 182 insertions(+) > > > > > > > ... > > You should be able to just move this into interrupts: > > interrupts: > > items: > > - description: > > alert-therm2 asserts when a diode temperature exceeds the > > ALERT > > threshold. > > - description: > > therm-addr asserts low when the hardware-set THERM limit > > threshold is > > exceeded by one of the temperature sensors. > > > > > + items: > > > + - const: alert-therm2 > > > + - const: therm-addr > > > > Also, should this and interrupts have minItems: 1? Are both actually > > required? Can you have therm-addr without alert-therm2? > > > > Right now the driver doesn't support any interrupts, but it may support > in future. The "alert-therm2" is a maskable interrupt and the "therm- > addr" can't be masked and is "always enabled" into the chip. > > I didn't use "minItems: 1" because I wanted to leave to the user the > decision if he needs any interrupts into their system Unfortunately, this doesn't work the way you expected. If you don't set minItems: 1, then anyone who wants to use an interrupt must use both. If someone that would connect therm-addr would always also connect alert-therm2, then minItems: 1 is enough to add. If someone might want to use therm-addr but not use alter-therm2, then this needs to be changed to permit these in any order. You can do that by adding the names as an enum, eg items: - enum: [ foo, bar] - bar
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